Pinch roll weft feeder with expandable transport roll

ABSTRACT

A transport roller (10) is provided on a ribbon loom and a press roller (12) is forced against said transport roller to grip a bobbin supply thread (26). In order to simplify adjustment of the transport speed while keeping the speed of the transport roller constant, a friction surface (32) is provided on the outside of the transport rollers casing or jacket (78) and can be expanded radially by an adjustment device (66, 72).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The innovation concerns a thread transport device for a textile machinehaving a drivable transport roller arranged on a shaft.

2. Description of the Prior Art

The most varied embodiments of thread transport devices are known. InGerman Patent DE-PS 946 177, a thread transport device of the typedescribed in the Field of the Invention relates to the feeding of aelastic thread to a circular knitting machine. In this known threadtransport device, the transport roller used for transporting the treadis situated on a friction disk and is supported by an arm, whose endthat is oriented away from the transport roller is pivotally attached toa guide shaft. The guide shaft is aligned in such a way that, as aresult of the longitudinal movement, the distance of the transportroller from the center of the friction disk can be changed, thereby alsochanging the circumferential speed of the transport roller. A contactpressure roller, positioned on the side of the transport roller orientedaway from the friction disk abuts and is supported on a lever of thetransport roller. The lever is pivoted on its end that is oriented awayfrom the contact pressure roller. The contact pressure force of thetransport roller on the friction disk, as well as the contact pressureforce of the contact pressure roller on the transport roller can bechanged and/or adjusted as a result of the lode weights. This knownthread transport device has certain disadvantages, including arelatively complicated design and a relatively large space requirementbecause of use of the friction disk. That is, a relatively large spaceis required because only one radial beam of one friction disk can beused, but space for the remainder of the friction disk must be madeavailable. It is also disadvantageous that the precision of the threadtransport is negatively affected by a number of effects, so that, forexample, a friction coefficient change results from the change of theoperating temperature between the cold and the warm state of themachine. Changes with respect to humidity, temperature and air pollutionalso cause friction coefficient changes, and, as a result, fluctuationsof the drive mechanism. The circular movement of the friction disk orthe transport roller as well as the fluctuating contact pressure canalso have a negative effect on the transport precision of the thread. Anadditional aggravation is the fact that the thread to be transportedlies simply between the contact pressure roller and the transport rollerand cannot be looped around the transport roller because otherwise itssupport by the friction roller would be negatively affected. As a resultof the relatively short contact path of the thread on the transportroller and/or the contact pressure roller, the additional disadvantageresults that slipping through of the thread at the transport roller canoccur, thus also subjecting the supply of the thread to inaccuracies.

The object of the innovation is additionally improving a threadtransport device of the type stated in the introduction in such a waythat the disadvantages of the state of the art are overcome.

The object is achieved by the characterizing features of the threadtransport device as described herein.

SUMMARY OF THE INVENTION

Because with an otherwise constant number of revolutions, the transportspeed can only be changed by expansion of the jacket of the transportroller with an otherwise constant number of revolutions, a particularlysimple design of the transport device results because the transportspeed can be adapted in the simplest manner by changing the diameter ofthe transport roller. As the transport roller diameter increases, with aconstant number of revolutions, an increase in the transport speedresults. Inversely, a reduction of the transport roller diameter leadsto a reduction in the conveying speed. The thread transport device canbe constructed in an extremely compact manner, therefore only requiresvery little space when being built into a machine. Additionally, thedesign of the device is very simple and hence cost-effective.

The jacket may be made of the most varied materials, for example from aroughened steel band strip that overlaps itself in a circumferentialdirection and is held by an expandable support device. More advantageousis an enhancement where the expandable jacket is of an elastomericmaterial which is particularly inexpensive and, at the same time, alsosupplies a jacket surface having an increased friction coefficient.

For the enhancement of the adjustment device, the most variedpossibilities also result, the use of a regulator block of substantiallyincompressible elastomer material positioned between the shaft and thejacket and support device being connected to the jacket, with theregulator block clamped in an axial position between two presser links,one being adjustable, presenting a very simple space-saving solutionshown and described herein. The adjustment process can proceed in a mostsimple manner in the enhancement where a threaded section is provided onthe shaft and arranged on an adjusting nut that interacts with anadjustable presser link, adjustment, however, in that case, only beingpossible with the thread transport device at a standstill.

An additional variant of the adjustment device is described herein,wherein the expandable jacket is conical on the side situated radiallyinside and interacts with a counterconical regulator on a shaft of atransport roller. The jacket and the counterconical regulator link gainadjustable realtive to each other in an axial direction by means of anadjusting device. The adjustment device necessary for adjustment can beembodied with a counterconical regulator link arranged to be stationaryon the shaft of the transport roller, and wherein the adjusting devicehas a sleeve acting laterially on the jacket which, by means of anyadjusting disk, is adjustable coaxial to the shaft of the transportroller. Here again, adjustment is only possible with the transportdevice at a standstill.

If the diameter of the thread transport roller is to be changeable evenduring operation, an enhancement characterized by a stationery adjustingdevice having driving means that interact with the presser link or theadjusting disk via a coupling link is advantageous. The stationaryadjustment device can be designed in the most varied manners, startingwith a simple adjusting screw, across a motor-driven spindle drive,through fluid-activated piston cylinder groups.

By arranging the contact pressure roller at the free portion of auniaterally pivoted lever which is pretensioned against the transportroller presents a particularly simple embodiment and support of thecontact pressure roller.

For the arrangement of the thread to be transported on the transportroller and on the contact pressure roller, the most varied possibilitiesresult. In the simplest case, contact between the thread to betransported and the transport roller and the drive roller can resultsimply by passing the thread through, at the point of contact, betweenthe transport roller and the contact pressure roller. The precision andsafety of the thread transport can be improved by the enhancement wherethe thread partially loops around the transport roller and can beremoved via the contact pressure roller, the thread also being partiallylooped around the contact pressure roller because, as a result of thepartial looping of the thread around the contact pressure roller, theapplicable friction force is considerably increased.

Fluctuations in the thread transport and/or thread use can becompensated by an enhancement of the thread transport device wherein thetransport roller and contact pressure roller are followed by a pneumaticcompensation device.

It may potentially be expedient to use the change in the transport speedcaused by a change in the diameter of the thread transport roller foradjustment and compensation purposes only and to perform major driveadjustments by an enhancement of the thread transport device where theshaft of the transport roller is connected to a variable speed drivingdevice. The mentioned advantages come to bear particularly in anenhancement of the thread transport device in accordance with thepreferred embodiment, where two and more thread transport rollers arearranged next to each other on a drivable shaft, their transportcharacteristics must, on the one hand, be adjusted to each other and, onthe other hand, to the thread use.

Sample embodiments of the object of the innovation are describedhereinafter in greater detail based on the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 A thread transport device on a ribbon loom in a schematicrepresentation.

FIG. 2 A transport roller and a contact pressure roller in a crosssection through their axes.

FIG. 3 The transport roller and the contact pressure roller of FIG. 2with a modified adjustment device.

FIG. 4 An additional transport roller with contact pressure roller aswell as an additional adjustment device in a cross section through theiraxes.

FIG. 5 A multiple arrangement of thread transport devices with a jointdrive in a schematic representation.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 shows a thread transport device 2 on a schematically representedribbon loom 4. The thread transport device comprises a drive mechanism6, which is coupled with the shaft 8 of a thread transport roller 10.Interacting with the latter, is a contact pressure roller 12, which isarranged rotatable on a lever 14, via a shaft 16. Lever 14 is attached,by the end oriented away from contact pressure roller 12, via a joint18, to a stationary carrier 20. A spring 22 is used for pretensioningthe contact pressure roller 12 against the thread transport roller 10.

Transport roller 10 pulls off a supply bobbin 24 a thread 26, which runsfirst through a thread brake 28 and a thread guide 30 before makingcontact with friction surface 32 of transport roller 10. Thread 26 isthen guided along part of the circumference of transport roller 10 andpasses under contact pressure roller 12 and is taking up from it, alsobeing guided along part of the circumference of contact pressure roller12. After contact pressure roller 12, via an additional thread guide 34,thread 26 reaches a pneumatic compensation device 36. The lattercomprises a narrow groove 38 through which the thread is guided via aninlet opening 40 and an outlet opening 42. A nozzle 44 blows an airblast into groove 38 and forms a thread loop 36 when the thread shows anexcess supply during processing.

From compensation device 36, via a stationary thread guide eye 48, thethread reaches a weft insertion needle 50, which introduces into shed 54a weft loop 52 of warps 56. On the side of the fabric that is orientedaway from weft insertion needle 50, a weaving needle 58 is used fortieing off weft loop 52. By means of a weaving reed 62, the weft loop iscast on weave point 64.

FIG. 2 shows a first embodiment of a transport roller 10 and a contactpressure roller 12. Transport roller 10 has, on shaft 8, a regulatorblock 66 that is formed of a quasi incompressible elastomer material.This regulator block is clamped between two presser links 68,70, thefirst presser link 68 of them being arranged stationary on shaft 8 andthe second presser link 70 consisting of a disk 70 that is movable onthe shaft and is tensionable, by means of an adjusting nut 72, againstthe first presser link 68. For this purpose, adjusting nut 72 isarranged on a threaded section 74 of the shaft. By compressing thepresser links 68,70, regulator block 66 is expanded in a radialdirection and acts, across a support device 76, for example in the formof cylindrical bodies or of a slotted sleeve with end sections thatoverlap in a circumferential direction, on a jacket 78, which formsfriction surface 32. Jacket 78 preferably also consists of elastomermaterial. By compressing regulator block 76 by means of the presserlinks 68,70, jacket 78 is pushed radially outward so that diameter Dincreases. During detensioning of regulator block 66 by means of thepresser links 68,70, jacket 78 contracts causing a reduction of diameterD. Situated on jacket 78, on friction surface 32, is thread 26, which ispushed, by means of contact pressure roller 12, against transport roller10. FIG. 2 also schematically indicates how contact pressure roller 12is arranged on shaft 16 and is held in place on lever 14, which, bymeans of spring 22, is pretensioned against transport roller 10.

FIG. 3 shows an arrangement of transport roller 10 and contact pressureroller 12 corresponding to FIG. 2, however, with adjusting nut 72 beingreplaced by a stationary adjusting device 80 formed of a dual-armcoupling link 82, which is pivotally supported by a stationary supportblock 84. At the end 86 that is oriented away from transport roller 10,coupling link 82 is connected to a driving means 88 that can be randomlydesigned, namely as anything from a simple regulating screw, to a driveshaft and even a fluid-activated cylinder group. The arm 90 that isoriented towards presser link 70 is designed forked and cooperates withpresser link 70 so that regulator block 66, can be more or lesscompressed as a function of the position of the driving means 88.

FIG. 4 shows an additional arrangement of a transport roller 10a and acontact pressure roller 12. Jacket 78a of transport roller 10a isdesigned conical on side 92 that is situated radially inside andcooperates with a counterconical regulator link 94, which is arrangedstationary on shaft 8a. An adjustment device 96 has a sleeve 98 thatacts laterally on jacket 78a and is supported by an adjusting disk 100that is arranged coaxial to shaft 8a. Adjusting disk 100 comprises, forthis purpose, a central threaded orifice 102, which is screwed to athreaded section 104 of shaft 8a. Adjusting device 96 determines, bymeans of adjusting disk 100, the axial position of jacket 78a on theconical regulator link 94, with diameter D of jacket 78a accordinglyincreased or reduced. Instead of adjusting disk 100 that can be screwedback and forth on shaft 8a, an external stationary regulating device canbe provided for activation of the disk, as described in FIG. 3.

FIG. 5 shows the arrangement of two thread transport devices 2a and 2b,which have been designed in analogy to the thread transport device ofFIGS. 1 and 2. These thread transport devices have a common shaft 8b andare activated by a joint driving device 6. The latter comprises a motor106 that drives a drive shaft 108, which is connected, via a variogear110, to shaft 8b of the thread transport devices. By changing thenumbers of revolutions of motor 106 and/or a change in the transmissionratio of variogear 110, the number of revolutions can be jointlyadjusted for all the thread transport devices 2a,2b. The threadtransport speed can be individually fine-tuned and adapted at theindividual ribbon looms 4a,4b, i.e. at the individual weaving stationsby means of the adjusting nuts 72 by adaptation of the diameter of thetransport rollers 10.

By means of the thread transport device in accordance with theinnovation, a whole set of significant advantages thus come about. Thus,an absolute, positive, and precise thread transport amount and itsadjustment is assured by:

a) The looping of the thread at the transport roller and the pressingdown of the thread by means of the contact pressure roller;

b) the thread quantity adjustment by increasing or decreasing thediameter of the transport roller diameter without changing the number ofrevolutions of the transport roller and/or

c) the individual tuning of several thread transport devices arranged ona joint drive shaft.

Based on the looping of the thread on the friction surface of the threadtransport device, on the one hand, and the pressing down of the threadby means of the contact pressure roller, on the other hand, a forcedcontrol results and a forced transport of the thread results that is notsusceptible to exterior effects such as temperature, climate andpollution. Finally, as a result of the extremely simple design andadjustment, the thread transport device is extremely space-saving andcan, therefore, be used and operated even in the most restricted areas.Furthermore, because of the very low number of components, it is notonly cost-effective but additionally shows reduced wear susceptibility.

As a result of the forced precise drive of the thread by means of thethread transport device, there is practically no slippage duringstarting and stopping of the weaving loom so that weaving defects thatotherwise frequently occur, are avoided. The same applies to an exactmaintenance of the band width as a result of the exact controlledfeeding of the thread for a weft insertion needle.

    ______________________________________                                        REFERENCE                                                                     ______________________________________                                        2             Thread transport device                                         2a            Thread transport device                                         2b            Thread transport device                                         4             Ribbon loom                                                     4a            Ribbon loom                                                     4b            Ribbon loom                                                     6             Drive mechanism                                                 8             Shaft                                                           8a            Shaft                                                           8b            Shaft                                                           10            Transport roller                                                10a           Transport roller                                                12            Contact pressure roller                                         14            Lever                                                           16            Shaft                                                           18            Joint                                                           20            Carrier                                                         22            Spring                                                          24            Supply bobin                                                    26            Thread                                                          28            Thread brake                                                    30            Thread guide                                                    32            Friction guide                                                  34            Thread guide                                                    36            Pneumatic compensation device                                   38            Groove                                                          40            Inlet opening                                                   42            Outlet opening                                                  44            Nozzle                                                          46            Thread loop                                                     48            Stationary thread guide eye                                     50            Weft insertion needle                                           52            Weft loop                                                       54            Shed                                                            56            Warp                                                            58            Weaving needle                                                  62            Weaving reed                                                    64            Weaving station                                                 66            Regulator block                                                 68            Stationary presser link                                         70            Presser link                                                    72            Adusting nut                                                    74            Threaded section                                                76            Support device                                                  78            Jacket                                                          78a           Jacket                                                          80            Stationary adjusting device                                     82            Couplig link                                                    84            Support block                                                   86            End of 82                                                       88            Driving means                                                   90            Forked arm                                                      92            Conical inside                                                  94            Regulator link                                                  96            Adjusting device                                                98            Sleeve                                                          100           Adjusting disk                                                  102           Threaded orifice                                                104           Threaded section                                                106           Motor                                                           108           Drive shaft                                                     110           Variogear                                                       ______________________________________                                    

I claim:
 1. A thread transport device for a textile machine, includingbut not limited to a ribbon loom comprising:a shaft; a drivabletransport roller with variable circumferential speeds and a frictionsurface arranged on said shaft; and a pretensioned contact pressureroller with inclusion of a thread to be transported, against thetransport roller, wherein the friction surface is formed by a seamlessjacket that is radially expandable by means of a regulator device, thetransport roller and the contact pressure roller are followed by apneumatic compensation device for the thread, and including at least twothread transport devices and a joint drivable shaft carrying said threadtransport devices.
 2. A thread transport device in accordance with claim1, wherein the expandable jacket consists of an elastomer material.
 3. Athread transport device in accordance with claim 2, wherein theregulator device has a regulator block of substantially incompressibleelastomer material arranged between the shaft and the jacket with asupport device being interconnected to the jacket, said regulator blockbeing clamped in an axial direction between two presser linkscounteracting each other, at least one of the presser links beingadjustable.
 4. A thread transport device in accordance with claim 2,wherein the regulator device includes a counterconical regulator link onsaid shaft carrying said transport roller, and the expandable jacket hasa conical inner side oriented toward said and interacting with saidcounterconical regulator link, and including an adjusting device forrelative axial adjustment between the jacket and the counterconicalregulator link.
 5. A thread transport device in accordance with claim 1,wherein the contact pressure roller is arranged at the free portion of aunilaterally pivoted lever, which is pretensioned against the transportroller.
 6. A thread transport device in accordance with claim 1, whereinthe thread partially loops around the transport roller and can beremoved via the contact pressure roller, the thread also being partiallylooped around the contact pressure roller.
 7. A thread transport devicein accordance with claim 1, wherein the shaft of the transport roller isconnected to a variable speed driving device.
 8. A thread transportdevice for a textile machine, including but not limited to a ribbon loomcomprising:a shaft; a drivable transport roller with variablecircumferential speeds and a friction surface arranged on said shaft;and a pretensioned contact pressure roller with inclusion of a thread tobe transported, against the transport roller, wherein the regulatordevice has a regulator block of substantially incompressible elastomermaterial arranged between the shaft and the jacket, with a supportdevice being interconnected to said jacket, said regulator block beingclamped, in an axial direction, between two presser links counteractingeach other, at least one of said presser links being adjustable.
 9. Athread transport device in accordance with claim 8, wherein, a threadedsection is provided on the shaft and is arranged on an adjusting nutthat interacts with the adjustable presser link.
 10. A thread transportdevice in accordance with claim 4, including a stationary adjustingdevice which comprises driving means that interact, via a coupling line,with the adjustable presser link.
 11. A thread transport device for atextile machine, including but not limited to a ribbon loom comprising:ashaft; a drivable transport roller with variable circumferential speedsand a friction surface arranged on said shaft; and a pretensionedcontact pressure roller with inclusion of a thread to be transported,against the transport roller, wherein the regulator device includes acounterconical regulator link on said shaft carrying said transportroller, and the expandable jacket has a conical inner side orientedtoward said and interacting with said counterconical regulator link, thejacket and the counterconical regulator link being adjustable relativeto each other in an axial direction by means of an adjusting device. 12.A thread transport device in accordance with claim 11, wherein thecounterconical regulator link is arranged stationary on the shaft of thetransport roller and that the adjusting device has a sleeve actinglaterally on the jacket which, by means of an adjusting disk, isadjustable coaxial to the shaft of the transport roller.
 13. A threadtransport device in accordance with claim 12, wherein the adjusting diskhas a central threaded orifice which is arranged on a threaded sectionof the shaft of the transport roller (10a).
 14. A thread transportdevice in accordance with claim 6, including a stationary adjustingdevice including driving means that interact with the presser link orthe adjusting link via a coupling link.
 15. A thread transport device inaccordance with claim 12, including a stationary adjusting device whichcomprises driving means that interact, via a coupling link 82, with theadjusting disk.
 16. A thread transport device for a textile machine,including but not limited to a ribbon loom comprising:a shaft; adrivable transport roller with variable circumferential speeds and afriction surface arranged on said shaft; and a pretensioned contactpressure roller with inclusion of a thread to be transported, againstthe transport roller, wherein the friction surface is formed by aseamless jacket that is radially expandable by means of a regulatordevice, and wherein the transport roller and the contact pressure rollerare followed by a pneumatic compensation device for the thread.
 17. Athread transport device for a textile machine, including but not limitedto a ribbon loom comprising:a shaft; a drivable transport roller withvariable circumferential speeds and a friction surface arranged on saidshaft; and a pretensioned contact pressure roller with inclusion of athread to be transported, against the transport roller, wherein thefriction surface is formed by a seamless jacket that is radiallyexpandable by means of a regulator device, and including at least twothread transport devices and a joint drivable shaft carrying said threadtransport devices.